Re: [Cocci] Changing format string usage with SmPL?

[Julia Lawall <julia.lawall@inria.fr>]

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> De: "Strace Labs" <stracelabs@gmail.com>
> À: "Julia Lawall" <julia.lawall@inria.fr>
> Cc: "cocci" <cocci@systeme.lip6.fr>
> Envoyé: Mercredi 4 Décembre 2019 01:28:22
> Objet: Re: [Cocci] Changing format string usage with SmPL?

> Unfortunately, it doesn't work. But, I am working on some solutions using
> Python.

> therefore, once we have something like:

> ...
> @r1@
> format list fl;
> identifier fn;
> expression list e;
> position p;
> @@

> fn("%@fl@", e@p)
> ....

> Then, I could handle the format list using make_expr() as well. But, Is it
> possible to rename/handle the expression list?

Could you fix up the expression list first? Then you can write a rule like 

char[] s; 

fn(s, ..., 
- oldcode 
+ newcode 
,...) 

julia 

> On Tue, Dec 3, 2019 at 3:18 AM Julia Lawall < [ mailto:julia.lawall@inria.fr |
> julia.lawall@inria.fr ] > wrote:

>>> De: "Strace Labs" < [ mailto:stracelabs@gmail.com | stracelabs@gmail.com ] >
>>> À: "Markus Elfring" < [ mailto:Markus.Elfring@web.de | Markus.Elfring@web.de ] >
>>> Cc: "Julia Lawall" < [ mailto:julia.lawall@inria.fr | julia.lawall@inria.fr ] >,
>>> [ mailto:cocci@systeme.lip6.fr | cocci@systeme.lip6.fr ]
>>> Envoyé: Mardi 3 Décembre 2019 11:30:14
>>> Objet: Re: [Cocci] Changing format string usage with SmPL?

>>> On Sun, Dec 1, 2019 at 6:00 AM Markus Elfring < [ mailto:Markus.Elfring@web.de |
>>> Markus.Elfring@web.de ] > wrote:

>>>>> Basically, I intend to replace alls "%s" called with "mydata->name" by "%m" with
>>>> > "mydata" or "&mydata"

>>>> How far would you get the desired source code transformation based on
>>>> software extensions around a search pattern like the following.
>>>> ..........
>>>> Which algorithm will become sufficient for your data processing needs
>>>> around the usage of functions with variadic arguments because of format strings?

>>> Actually, I really didn't get why you're asking about that. because we are
>>> talking about X and you're asking for Y. but, either way. that is not the
>>> point. the point is because I am studying about the Coccinelle and I am just
>>> trying to figure out if the tool could detect "%s" called with "mydata->name"
>>> and then replace by "%m" and remove the "->name"

>>> e.g: Once if we have:

>>> int foo() {
>>> int id;
>>> struct mydata h1, *h2, s1, *s2;
>>> char *city = "Hello";
>>> my_printf("%s", s2->name);
>>> my_printf("hi hi %s gggg", [ http://h1.name/ | h1.name ] );
>>> my_printf("1234 %d %s @ %d %s | %s -> city=%s", id, [ http://s1.name/ | s1.name
>>> ] , 12, (*h2).name , h2->name , city);
>>> my_printf("aaaa %s hhhhh", h2->name);
>>> my_printf("%s", city);
>>> }

>>> Then, replace by:

>>> int foo() {
>>> int id;
>>> struct mydata h1, *h2, s1, *s2;
>>> char *city = "Hello";
>>> my_printf("%m", s2);
>>> my_printf("hi hi %s gggg", &h1);
>>> my_printf("1234 %d %m @ %d %m | %m -> city=%s", id, [ http://s1.name/ | s1.name
>>> ] , 12, (*h2).name , h2->name , city);
>>> my_printf("aaaa %s hhhhh", h2);
>>> my_printf("%s", city);
>>> }

>>> But, I've read again the other samples and the documentation. therefore, I
>>> didn't figure out how it should be. btw, thank you Julia for the suggestion
>>> performing the Ocalm/make_expr/replace . (Due to something wrong with the
>>> Coccinelle distributed by Brew/Osx. I just rewrote your sample using Python and
>>> the result was the same. But, I can't just replace all "%s" by "%m". As I said,
>>> it should be only if the "%s" was declared to use "mydata->name".

>>> so, I still fighting yet. thanks in Advance.

>> OK, if you may have more than one argument to your print, then you can find the
>> offset using an expression list metavariable:

>> @r@
>> expression list[n] between;
>> @@

>> print(s,between,h2->name,...)

>> Then you can use r.n in your python rule to figure out where is the %s to
>> change. Unfortunately, this will not work well if there are multiple name
>> references in the argument list. Because you will be trying to change the
>> format string in multiple ways, eg once where between has length 2 and once
>> where between has length 4. Substantial hacks would be required to deal with
>> this.

>> It would be nice if you could do

>> @r@
>> expression list[bn] between;
>> expression list[an] after;
>> position p;
>> @@
>> print@p(s,between,name,after)

>> @@
>> format list[ [ http://r.bn/ | r.bn ] ] f1;
>> format list[ [ http://r.an/ | r.an ] ] f2;
>> position r.p;
>> @@
>> print@p(
>> - "%@f1@%s%@f2@"
>> + "%@f1@%m%@f2@"
>> , l)

>> I don't know if that would work, though.

>> julia

>>>> Regards,
>>>> Markus

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